From: Ludovic Barre ludovic.barre@st.com
[ Upstream commit 33ba6fec0012e47f4e72bfab922b99327373f210 ]
This patch fix a power-on issue, and avoid to retry the power sequence.
In power off sequence: sdmmc must set pwr_reg in "power-cycle" state (value 0x2), to prevent the card from being supplied through the signal lines (all the lines are driven low).
In power on sequence: when the power is stable, sdmmc must set pwr_reg in "power-off" state (value 0x0) to drive all signal to high before to set "power-on".
To avoid writing the same value to the power register several times, this register is cached by the pwr_reg variable. At probe pwr_reg is initialized to 0 by kzalloc of mmc_alloc_host.
Like pwr_reg value is 0 at probing, the power on sequence fail because the "power-off" state is not writes (value 0x0) and the lines remain drive to low.
This patch initializes "pwr_reg" variable with power register value. This it done in sdmmc variant init to not disturb default mmci behavior.
Signed-off-by: Ludovic Barre ludovic.barre@st.com Link: https://lore.kernel.org/r/20200420161831.5043-1-ludovic.barre@st.com Signed-off-by: Ulf Hansson ulf.hansson@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/mmc/host/mmci_stm32_sdmmc.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/mmc/host/mmci_stm32_sdmmc.c b/drivers/mmc/host/mmci_stm32_sdmmc.c index cca7b3b3f618..2965b1c062e1 100644 --- a/drivers/mmc/host/mmci_stm32_sdmmc.c +++ b/drivers/mmc/host/mmci_stm32_sdmmc.c @@ -522,6 +522,7 @@ void sdmmc_variant_init(struct mmci_host *host) struct sdmmc_dlyb *dlyb;
host->ops = &sdmmc_variant_ops; + host->pwr_reg = readl_relaxed(host->base + MMCIPOWER);
base_dlyb = devm_of_iomap(mmc_dev(host->mmc), np, 1, NULL); if (IS_ERR(base_dlyb))